Magnetic transfer method and apparatus

ABSTRACT

A favorable magnetic transfer is performed on a perpendicular magnetic recording medium. A permanent magnet apparatus provided with two permanent magnets, each having a width extending the length of the radial direction of a discoid magnetic recording medium, is used as a transfer magnetic field generating means. A conjoined body formed of the perpendicular magnetic recording medium, which has been initially magnetized unidirectionally in the direction perpendicular to the track surface thereof, and two master mediums, disposed on respective surfaces of the slave medium, is inserted between the permanent magnets. A rotating means rotates the conjoined body, in the direction along the tracks of the slave medium, while a transfer magnetic field is applied to the conjoined body in the direction substantially opposite that in which the initial magnetization of the magnetic layer of magnetic recording medium has been performed, so as to perform the magnetic transfer.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates in general to a magnetic transfermethod of conjoining the magnetic layer of a magnetic transfer mastermedium, which has been formed in a pattern for transferring data to amagnetic recording medium, and the magnetic layer of a slave medium toform a conjoined body, and applying a transfer magnetic field to saidconjoined body so as to magnetically transfer the data borne by thepattern of the magnetic layer of the master medium to the magnetic layerof the slave medium.

[0003] Description of the Related Art

[0004] Generally speaking, with regard to magnetic storage mediums,there is a demand for increased storage capacity and low cost. Furtherdesired are so-called high-speed access mediums, which are capable ofadvantageously reading out the data of a desired location in a shorttime. Examples of these mediums include the high density magneticrecording mediums (magnetic disk mediums) utilized in hard diskapparatuses and floppy (R) disk apparatuses. So-called tracking servotechnology, wherein the magnetic head accurately scans a narrow widthtrack to achieve a high S/N ratio, plays a substantial role in attainingthe high storage capacity thereof. A servo signal, address data signal,replay clock signal, etc., used for tracking within a certain intervaloccurring in one rotation of the disk are “preformatted”, that is,recorded on the disk in advance.

[0005] Magnetic transfer methods realizing accurate and efficientpreformatting, wherein the data such as a servo signal or the like borneon a master medium is magnetically transferred therefrom to a magneticrecording medium, have been proposed in, for example, JapaneseUnexamined Patent Publication Nos. 63(1988)-183623, 10(1998)-40544, and10(1998)-269566.

[0006] According to these magnetic transfer technologies, a mastermedium having an uneven pattern corresponding to the data that is to betransferred to a slave medium (a magnetic recording medium) is prepared.By bringing this master medium brought into close contact with a slavemedium to form a conjoined body, and applying a transfer magnetic fieldthereto, a magnetic pattern corresponding to the data (e.g., a servosignal) borne on the master medium is transferred to the slave medium.The preformatting can be performed without changing the relativepositions of the master medium and the slave medium—that is, while thetwo media remain static. Therefore not only is it possible to perform anaccurate recording of the preformat data, it becomes possible toadvantageously do so in an extremely short time.

[0007] However, as to the magnetic recording medium, two possibilitiesare longitudinal magnetic recording mediums provided with a goodmagnetization axis in the longitudinal direction in relation to thesurface of the magnetic layer thereof, and perpendicular magneticrecording mediums provided with an easy magnetization axis in theperpendicular direction in relation to the surface of the magnetic layerthereof; however, in current practice, longitudinal magnetic recordingmediums are generally employed, and the magnetic transfer technologydescribed above has also been developed focusing mainly on thelongitudinal magnetic recording mediums as the magnetic recording mediumof choice. On the other hand, if a perpendicular magnetic recordingmedium is employed, in comparison to the longitudinal magnetic recordingmediums, an increase in data storage capacity can be expected.

[0008] For cases in which a magnetic transfer is performed on aperpendicular magnetic recording medium, a magnetic field must beapplied in the perpendicular direction with respect to the surface ofthe magnetic layer thereof; wherein the optimal conditions differ withrespect to cases in which a magnetic transfer is performed on alongitudinal magnetic recording medium.

SUMMARY OF THE INVENTION

[0009] The present invention has been developed in view of the forgoingcircumstances, and it is an object of the present invention to provide amagnetic transfer master medium capable of performing a favorablemagnetic transfer onto a perpendicular magnetic recording medium.

[0010] The magnetic transfer method according to the present inventionis a magnetic transfer method comprising the steps of: conjoining thedata bearing surface, which consists of a magnetic layer formed in apattern corresponding to the data to be transferred to the magneticlayer of a slave medium, of a master medium with the magnetic layer ofsaid slave medium to form a conjoined body, and applying a transfermagnetic field to the respective magnetic layers of the conjoined mastermedium and slave medium to magnetically transfer the data to the slavemedium, wherein

[0011] the slave medium is a perpendicular magnetic recording medium,and after the magnetic layer of said slave medium has been subjected toan initial magnetization process consisting of applying an initialdirect current magnetic field to said magnetic layer unidirectionally inthe direction perpendicular to the track direction thereof to initiallymagnetize said magnetic layer, the magnetic layer of the slave mediumand the magnetic layer of the master medium are conjoined and a transfermagnetic field is applied to the respective magnetic layers thereof inthe direction opposite that in which the initial direct currentmagnetization has been performed.

[0012] Here, the expression “magnetically transfer the data” refers tothe formation of a pattern, which corresponds to said data, on themagnetization array of the magnetic layer of the slave medium.

[0013] Further, the referents of “conjoined” include not only the statewherein the respective surfaces of both of said mediums are in completecontact with each other, but also states wherein said mediums aredisposed in a state wherein a uniform interval is maintained between therespective surfaces thereof.

[0014] Still further, the initial magnetization of the slave medium canbe performed while the slave medium and the master medium are in theconjoined state, or while the slave medium and the master medium are notin the conjoined state. For the case in which the initial magnetizationis performed while the master medium and the slave medium are not in theconjoined state, the slave medium can be conjoined with the mastermedium after the initial magnetization thereof has been performed.

[0015] In addition, according to the magnetic transfer method of thepresent invention, the intensity of the transfer magnetic field isgreater than or equal to 0.5 times and less than or equal to 3.5 timesthe magnetic coercive force of the slave medium.

[0016] Further, the conjoined body formed of the conjoined master mediumand slave medium can be moved relative to the transfer magnetic field,which is generated over an area that is narrower than the track region,so as to pass the entirety of the track region of said slave mediumthrough the transfer magnetic field.

[0017] In particular, for cases in which the slave medium is a discoidshape having concentric circular tracks, the aforementioned regionnarrower than the track region can be made to have a width spanning asingle region extending in the radial direction of the track from thetrack of the smallest radius of the slave medium to the track of thelargest radius of the slave medium; wherein the aforementioned relativemovement can consist of rotating the slave medium an amountcorresponding to the complete track thereof.

[0018] Here, the track region of the slave medium and the concentriccircular tracks refer to the track region formed by the magnetictransfer as well as the concentric tracks.

[0019] Note that the movement relative to the transfer magnetic fieldmay be movement of the slave medium and the master medium, or,alternatively, movement of the transfer magnetic field.

[0020] The magnetic transfer method according to the present inventionis a magnetic transfer method comprising the steps of: conjoining thedata bearing surface, which consists of a magnetic layer formed in apattern corresponding to the data to be transferred to the magneticlayer of a slave medium, of a master medium with the magnetic layer ofsaid slave medium to form a conjoined body, and applying a transfermagnetic field to the respective magnetic layers of the conjoined mastermedium and slave medium to magnetically transfer the data to the slavemedium, and can be implemented by a magnetic transfer apparatuscomprising:

[0021] an initial magnetizing means for subjected the slave medium to aninitial magnetization process consisting of applying an initial directcurrent magnetic field to said magnetic layer unidirectionally in adirection perpendicular to the track surface thereof to initiallymagnetize said magnetic layer unidirectionally in the directionperpendicular to said track surface, and

[0022] a transfer magnetic field applying means for applying a transfermagnetic field to the conjoined body formed of the conjoined mastermedium and slave medium in the direction opposite that in which theinitial direct current magnetization has been performed.

[0023] According to the magnetic transfer apparatus described above, thetransfer magnetic field applying means can be a means comprising: atransfer magnetic field generating means for generating a transfermagnetic field on a region of the slave medium narrower than the trackregion thereof, and a moving means for moving the conjoined body formedof the master medium and slave medium, which have their respectivemagnetic layers in close contact with each other, relative to saidtransfer magnetic field so as to pass the entirety of the track regionof said slave medium through the transfer magnetic field.

[0024] Further, the transfer magnetic field generating means can be ameans for generating a transfer magnetic field over the region extendingin the radial direction from the track of the smallest radius of adiscoid slave medium to the track of the largest radius of said slavemedium having concentric circular tracks; wherein the moving means canbe a means for rotating the discoid slave medium a complete rotationalong the tracks thereof.

[0025] Still further, for cases in which the slave medium is a discoidperpendicular recording medium having concentric circular tracks, afterthe magnetic layer of said slave medium has been subjected to an initialmagnetization process consisting of applying an initial direct currentmagnetic field to said magnetic layer unidirectionally in the directionperpendicular to the track direction thereof to initially magnetize saidmagnetic layer,

[0026] a transfer magnetic field can be generated across a regionnarrower than the track region of the slave medium and having a widthlarger than that of the track of the largest radius, in the directionopposite that in which the initial direct current magnetization has beenperformed, to perform the magnetic transfer; wherein

[0027] the conjoined body formed of the conjoined slave medium andmaster medium can be moved relative to the transfer magnetic field so asto pass the entirety of said track surface of the slave medium throughsaid transfer magnetic field.

[0028] The magnetic transfer method according to the present inventionis a magnetic transfer method comprising the steps of: conjoining thedata bearing surface, which consists of a magnetic layer formed in apattern corresponding to the data to be transferred to the magneticlayer of a slave medium, of a master medium with the magnetic layer ofsaid slave medium to form a conjoined body, and applying a transfermagnetic field to the respective magnetic layers of the conjoined mastermedium and slave medium to magnetically transfer the data to the slavemedium, and can be implemented by a magnetic transfer apparatuscomprising:

[0029] an initial magnetizing means for subjecting a discoid slavemedium having concentric circular tracks to an initial magnetizationprocess consisting of applying an initial direct current magnetic fieldto said magnetic layer unidirectionally in the direction perpendicularto the track surface thereof to initially magnetize said magnetic layerunidirectionally in the direction perpendicular to said track surface,and

[0030] a transfer magnetic field applying means for generating atransfer magnetic field across a region narrower than the track regionof the slave medium and having a width larger than that of the track ofthe largest radius, in the direction opposite that in which the initialdirect current magnetization has been performed, to perform the magnetictransfer; wherein

[0031] the conjoined body formed of the conjoined slave medium andmaster medium can be moved relative to the transfer magnetic field so asto pass the entirety of said track surface of the slave medium throughsaid transfer magnetic field.

[0032] Note that according to each magnetic transfer apparatus describedabove, the transfer magnetic field applying means may also serve as theinitial magnetizing means.

[0033] Further, as to the transfer magnetic field generating means forapplying the transfer magnetic field, although an electromagneticapparatus or a permanent magnetic apparatus can be employed thereas,from the standpoint of the setting and adjustability of the intensity ofthe magnetic field and other such conditions, it is preferable that anelectromagnetic apparatus be employed. On the other hand, whenperforming a magnetic transfer at a fixed magnetic field intensity, fromthe standpoints of cost effectiveness and the ability to compactlyconfigure the apparatus, employing a permanent magnetic apparatus ispreferable.

[0034] According to the magnetic transfer method of the presentinvention: after subjecting the slave medium to an initial directcurrent magnetization unidirectionally in the direction perpendicular tothe track surface thereof, by conjoining the magnetic layer of the slavemedium with the magnetic layer of a master medium to form a conjoinedbody, and applying a transfer magnetic field to said conjoined body inthe direction opposite that in which the initial direct currentmagnetization has been performed so as to perform a magnetic transfer, afavorable magnetic transfer can be performed on a perpendicular magneticrecording medium.

[0035] In particular, by making the intensity of the transfer magneticfield greater than or equal to 0.5 times and less than or equal to 3.5times the coercive force of the magnetic layer of the slave medium, themagnetic transfer can be performed more accurately.

[0036] Note that if the magnetic transfer is performed such that theconjoined body formed of the conjoined master medium and slave medium ismoved relative to the transfer magnetic field, which is generated overan area that is narrower than the track region, so as to pass theentirety of the track region of said slave medium through said transfermagnetic field, the manufacture of preformatted slave mediums can beperformed easily and efficiently.

[0037] In particular, if the magnetic transfer is performed by use of amethod wherein the transfer magnetic field is generated over the regionof a discoid slave medium, which has concentric circular tracks,extending in the radial direction from the track of the smallest radiusthereof to the track of the largest radius thereof, and the conjoinedbody formed of the conjoined master medium and slave medium is rotatedso as to perform the magnetic transfer, the magnetic transfer to a diskshaped magnetic recording medium or the like can be efficientlyperformed by use of a simple apparatus configuration.

[0038] Further, if the magnetic transfer is performed by use of a methodwherein the transfer magnetic field is generated over the region of adiscoid slave medium narrower than the track region of the said slavemedium and having a width larger than that of the track of the largestradius, so as to perform the magnetic transfer; wherein the conjoinedbody formed of the conjoined slave medium and master medium is movedrelative to the transfer magnetic field so as to pass the entirety ofsaid track surface of the slave medium through said transfer magneticfield, because it becomes possible to perform the magnetic transferacross the entirety of the track surface by moving the conjoined bodylinearly, without any complicated rotational movement or the like, themagnetic transfer to a disk shaped magnetic recording medium or the likecan be performed efficiently and more easily.

BRIEF DESCRIPTION OF THE DRAWINGS

[0039]FIG. 1 is a perspective view of the main part of a transfermagnetic field applying means implementing the magnetic transfer methodaccording to the first embodiment of the present invention,

[0040]FIG. 2 is a perspective view of a master medium and a slavemedium,

[0041]FIGS. 3A, 3B, and 3C are drawings illustrating the basic processesof a magnetic transfer method,

[0042]FIG. 4 is a schematic drawing of a variation on the firstembodiment,

[0043]FIG. 5 is a perspective view of the main part of a transfermagnetic field applying means implementing the magnetic transfer methodaccording to the second embodiment of the present invention, and

[0044]FIG. 6 is a schematic drawing of a variation on the secondembodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0045] Hereinafter the preferred embodiments of the present inventionwill be explained with reference to the attached drawings. FIG. 1 is aperspective view of the main part of a transfer magnetic field applyingmeans implementing the magnetic transfer method according to the firstembodiment of the present invention.

[0046] The transfer magnetic field applying means 1 shown in FIG. 1comprises a permanent magnet apparatus 5, which is a magnetic fieldgenerating means, provided with two permanent magnets 5 a and 5 b, and arotating means (not shown) for rotating a conjoined body 10, which isformed of the a discoid slave medium 2 and two discoid master mediums 3,4 disposed on respective surfaces of the slave medium 2, in thedirection indicated by the arrow A.

[0047] The permanent magnets 5 a and 5 b of the permanent magnetapparatus 5 are each of a width that at least spans from the smallestradius track r_(min) to the largest radius track r_(max) of the slavemedium 2 shown in FIG. 2, and are disposed with the respective oppositemagnetic pole faces thereof opposed so as to generate a magnetic fieldHdu from the lower to the upper direction of the conjoined body 10.Further, because it is necessary that ample space be provided betweenthe upper and lower permanent magnets 5 a, 5 b of the permanent magnetapparatus so as to facilitate the unobstructed insertion and removal ofthe conjoined body 10 therebetween, the permanent magnet apparatus isalso provided with a separating means (not shown) for mutuallyseparating the permanent magnets 5 a and 5 b. Note that the magneticfield Hdu is set so as to be from 0.5 to 3.5 times the intensity of thecoercive force Hcs of the slave medium.

[0048]FIG. 2 is an exploded view of a conjoined body 10. The conjoinedbody 10 is formed of a slave medium 2, each respective magnetic layer 2b, 2 c thereof with which the surface of the pattern of protrusionportions, which form a pattern on the respective master mediums 3 a and4 a are conjoined; wherein, the radial direction of the respectivesurfaces of the slave medium 2 is matched with the width direction ofthe respective permanent magnet 5 a, 5 b when the slave medium 2 is settherebetween.

[0049] The slave medium utilized according to the magnetic transfermethod of the present invention is a disk shaped magnetic recordingmedium such as a hard disk, a flexible disk, or the like, which has beenprovided with a magnetic recording layer on a single surface or on bothsurfaces thereof; in particular, a perpendicular magnetic recordingmedium on which an easily magnetizable direction of the magneticrecording layer has been formed in the direction perpendicular to therecording surface thereof is utilized thereas. The slave medium 2 shownin FIG. 2 is a perpendicular magnetic recording medium, which isrecordable on both surfaces thereof, on which magnetic layers (magneticrecording layers) 2 b, 2 c, are formed on both surfaces of the substrate2 a thereof, respectively.

[0050] The master medium 3 is provided with protrusion portions formedin a pattern corresponding to the data to be recorded onto the lowerrecording surface 2 b of the slave medium 2. The master medium 4 is ofthe same layered configuration as the master medium 3, and is providedwith protrusion portions formed in a pattern corresponding to the datato be recorded onto the upper recording surface 2 c of the slave medium2. The master mediums 3, 4 comprise a substrate 3 a, 4 a, respectively,on each of which a pattern of protrusion portions has been formed, and amagnetic layer 3 b, 4 b, formed on the surface of said substrate.

[0051] Next, the magnetic transfer method according to the presentinvention will be explained. First, with reference to FIGS. 3A, 3B, and3C, the basic processes of the magnetic transfer will be explained. FIG.3A illustrates the process wherein an initial magnetic field is appliedunidirectionally to the slave medium so as to perform the initialmagnetization thereof. FIG. 3B illustrates the process wherein the slavemedium and the master medium are conjoined to form a conjoined body, anda transfer magnetic field is applied thereto in the direction oppositethat in which the initial magnetization has been performed. FIG. 3Cshows the state of the recording surface of the slave medium after themagnetic transfer has been performed. Note that, FIG. 3 illustrates thelower face recording surface 2 d of the slave medium and the lowermaster medium 3, and an explanation has been given for only the magnetictransfer to said lower face recording surface 2 b; however, a magnetictransfer to the upper face recording surface 2 c can be performed in thesame manner.

[0052] As shown in FIG. 3A, an initial direct current magnetic field Hinis applied in the direction perpendicular to the track surface of the ofthe slave medium 2 in advance, so as to initially magnetize therecording surface 2 b thereof in one direction. Then, as shown in FIG.3B, the surface of the recording layer 2 b of this slave medium 2 isconjoined with the pliable magnetic layer 3 b on the surface of theprotrusion portions of the master medium 3 to form a conjoined body, anda transfer magnetic field Hdu is applied thereto in the perpendicular tothe recording layer 2 b of the slave medium 2 and in opposite directionthat the initial direct current magnetic field Hin has been applied(i.e., in the direction opposite the direction in which the initialmagnetization has been performed) to perform the magnetic transfer. As aresult, the data (a servo signal, for example) corresponding to thepattern of protrusion portions formed on the surface of the mastermedium 3 is magnetically transferred and recorded on the magneticrecording surface 2 b of the slave medium 2, as shown in FIG. 3C.

[0053] Note that, even for cases in which the uneven pattern of themaster medium 3 is a negative pattern, the opposite to that of thepositive pattern shown in FIG. 3B, by reversing the above describeddirections in which the initial direct current magnetic field Hin andthe transfer magnetic field Hdu are applied, the same data can bemagnetically transferred and recorded.

[0054] Next, the magnetic transfer method employing the transfermagnetic field applying means shown in FIG. 1 will be explained.

[0055] First, the initial magnetization of the magnetic layers 2 b, 2 cof the slave medium 2 is performed by use of an initial direct currentmagnetizing means (not shown). That is to say, an initial direct currentmagnetic field Hin is applied to the magnetic layers 2 b, 2 c in thedirection perpendicular thereto, whereby the initial magnetization ofthe magnetic layers is performed.

[0056] Then, the pattern of protrusion portions on each of the mastermediums 3, 4 is conjoined to the magnetic layers 2 b, 2 c, respectivelyof the slave medium to form a conjoined body 10. Next, the conjoinedbody 10 is inserted between the permanent magnets 5 a, 5 b of thepermanent magnet apparatus 5, wherein there is ample space separatingsaid permanent magnets 5 a, 5 b, so that the transfer magnetic field Hducan be applied thereto in the direction opposite that in which theinitial magnetization of the magnetic layers 2 b, 2 c of the slavemedium has been performed. Then, the permanent magnets 5 a, 5 b are madeto approach the respective surfaces of the conjoined body 10, and thetransfer magnetic field Hdu is applied. The conjoined body 10 is rotatedone full rotation in the direction indicated by the arrow A by arotating means (not shown) while the permanent magnets are in thevicinity of the conjoined body 10.

[0057] According to the current embodiment, the magnetic layers 2 b, 2 cof the slave medium have been initially magnetized in advance, and thenthe master mediums 3, 4 have been conjoined therewith, respectively;however, the initial magnetization of the magnetic layers 2 b, 2 c ofthe slave medium 2 can be performed in the state wherein the slavemedium 2 has been conjoined with the master mediums 3, 4 in advance.

[0058] Further, according to the current embodiment, the conjoined body10 has been rotated relative to the transfer magnetic field Hdu;however, a configuration wherein the permanent magnets 5 a, 5 b arerotated relative to the conjoined body, which has been fixed in astationary position, can also be employed.

[0059] According to the magnetic transfer apparatus of the presentembodiment, a magnetic transfer to a perpendicular magnetic transfermedium can be performed easily, and moreover, the quality of saidtransfer is high. By enabling a favorable magnetic transfer to beperformed to a perpendicular magnetic transfer medium, magneticrecording mediums having a larger storage capacity in comparison toconvention high-density planar recording mediums can be easily obtained.

[0060] Further, the transfer magnetic field applying means can be ameans comprising a transfer magnetic field generating means, and amoving means; in particular, by making the transfer magnetic fieldgenerating means a means for generating a transfer magnetic field overthe region extending in the radial direction from the track of thesmallest radius of a discoid slave medium to the track of the largestradius of said slave medium having concentric circular tracks, and themoving means a means for rotating the discoid slave medium relative tothe transfer magnetic field a complete rotation along the track thereof,the performance of a magnetic transfer to a discoid recording mediumsuch as a hard disc or a flexible disk can be optimized, and themagnetic transfer can be performed efficiently by an apparatus of asimple configuration.

[0061] Further, the transfer magnetic field applying means 1 can also beused as the initial direct current magnetizing means. In this case, theupper and lower surfaces of the slave medium can be set between thepermanent magnets 5 a, 5 b so that the magnetic layers 2 b, 2 c thereofare reversed when the transfer magnetic field is to be applied, wherebythe direction in which the transfer magnetic field Hdu is appliedthereto is the opposite of that in which the initial direct currentmagnetic field Hin was applied.

[0062] By combining the transfer magnetic field applying means and theinitial direct current magnetizing means into an integrated unit, thecost of the apparatus can be kept low, and it becomes possible toprovide preformatted magnetic recording mediums at an inexpensive price.

[0063] Note that it is necessary that the value employed for theintensity of the transfer magnetic field and the initial direct currentmagnetic fields be determined based on consideration of the coerciveforce of the slave medium, the relative permeability of the mastermedium and the slave medium, or the like. However, as described above,the intensity of the transfer magnetic field is to be a value greaterthan or equal to 0.05 times and less or equal to than 3.5 times thecoercive force Hcs of the slave medium.

[0064] According to the above-described embodiment, although a permanentmagnet apparatus 5 has been employed for explanatory purposes as themagnetic field generating means, an electromagnetic apparatus 15 such asthat shown in FIG. 4 can also be employed thereas. The electromagneticapparatus 15 shown in FIG. 4 is disposed both above an below theconjoined body 10, and comprises a core 16, which is of a widthcorresponding to the length in the radial direction of the conjoinedbody, having a predetermined gap, and around which a coil 17 has beenwound. The magnetic transfer method employing this electromagneticapparatus 15 is substantially the same as that described above. If theelectromagnetic apparatus 15 is employed, it becomes possible to easilychange the direction and intensity of the magnetic field.

[0065]FIG. 5 is a perspective view of the main part of a transfermagnetic field applying means implementing the magnetic transfer methodaccording to the second embodiment of the present invention.

[0066] According to the magnetic transfer method of the secondembodiment, unlike the magnetic transfer method of the first embodiment,the magnetic disk or the magnetic field generating means is not rotatedthe one relative to the other; however, the magnetic transfer method ofthe second embodiment is a method wherein it is possible to perform themagnetic transfer across the entire track surface of the slave medium byonly a linear motion of the magnetic disk or the magnetic fieldgenerating means.

[0067] The transfer magnetic field applying means shown in FIG. 5comprises a permanent magnet apparatus 105, which is a magnetic fieldgenerating means, provided with two permanent magnets 105 a and 105 b,and a moving means (not shown) for moving the conjoined body 10, whichis formed of the a discoid slave medium 2 and two discoid master mediums3, 4 disposed on respective surfaces of the slave medium 2, in thedirection indicated by the arrow.

[0068] As shown in FIG. 2 the permanent magnets 105 a and 105 b of thepermanent magnet apparatus 105 are each of a width equivalent to thelength of the diameter d of the slave medium 2, and are disposed withthe respective opposite magnetic pole faces thereof opposed so as togenerate a magnetic field Hdu oriented from the lower to the upperdirection of the conjoined body 10. Note that the magnetic field Hdu isset so as to be from 0.5 to 3.5 times the intensity of the coerciveforce Hcs of the slave medium.

[0069] First, the initial magnetization of the magnetic layers 2 b, 2 cof the slave medium 2 is performed by use of an initial direct currentmagnetizing means (not shown). That is to say, an initial direct currentmagnetic field Hin is applied to the magnetic layers 2 b, 2 c in adirection perpendicular thereto, whereby the initial magnetization ofthe magnetic layers is performed.

[0070] Then, the surface of the pattern of protrusion portions, whichform a pattern on the surface of each of master mediums 3, 4 isconjoined to the magnetic layers 2 b, 2 c, respectively, of the slavemedium to form a conjoined body 10. Next, the conjoined body 10 is movedin the direction indicated by the arrow and passed through the permanentmagnets 105 a, 105 b so that the transfer magnetic field Hdu is appliedto the entire surface thereof in the direction opposite that in whichthe initial magnetization of the magnetic layers 2 b, 2 c of the slavemedium has been performed.

[0071] According to the current embodiment, the magnetic layers 2 b, 2 cof the slave medium have been initially magnetized in advance, and thenthe master mediums 3, 4 have been conjoined therewith, respectively;however, the initial magnetization of the magnetic layers 2 b, 2 c ofthe slave medium 2 can be performed in the state wherein the slavemedium 2 has been conjoined with the master mediums 3, 4 in advance.

[0072] According to the current embodiment, the conjoined body 10 hasbeen moved relative to the transfer magnetic field Hdu; however, aconfiguration wherein the permanent magnets 5 a, 5 b can be movedrelative to the conjoined body, which has been fixed in a stationaryposition can also be adopted.

[0073] Further, according to the magnetic transfer apparatus of thecurrent embodiment, because the transfer magnetic field applying meanscomprises a magnetic field generating means for generating a transfermagnetic field across a region smaller than the track region of theslave medium and having a width larger than that of the track of thelargest radius, and in the direction opposite that in which the initialdirect current magnetization has been performed, it becomes possible toperform the magnetic transfer across the entirety of the track surfaceof the slave medium by moving, by use of the moving means, the conjoinedbody formed of the conjoined slave medium and master medium through thetransfer magnetic field in only a linear direction; whereby the movingmeans can be of a simplified configuration.

[0074] Further, the transfer magnetic field applying means 1 can also beused as the initial direct current magnetizing means. In this case, theupper and lower surfaces of the slave medium can be set between thepermanent magnets 5 a, 5 b so that the magnetic layers 2 b, 2 c thereofare reversed when the transfer magnetic field is to be applied, wherebythe direction in which the transfer magnetic field Hdu is appliedthereto is the opposite of that in which the initial direct currentmagnetic field Hin was applied.

[0075] By combining the transfer magnetic field applying means and theinitial direct current magnetizing means into an integrated unit, thecost of the apparatus can be kept low, and it becomes possible toprovide preformatted magnetic recording mediums at an inexpensive price.

[0076] Note that it is necessary that the value employed for theintensity of the transfer magnetic field and the initial direct currentmagnetic fields be determined based on consideration of the coerciveforce of the slave medium, the relative permeability of the mastermedium and the slave medium, or the like. However, as described above,the intensity of the transfer magnetic field is to be a value greaterthan or equal to 0.05 times and less or equal to than 3.5 times thecoercive force Hcs of the slave medium.

[0077] According to the second embodiment, although a permanent magnetapparatus 105 has been employed for explanatory purposes as the magneticfield generating means, an electromagnetic apparatus 115 such as thatshown in FIG. 6 can also be employed thereas. The electromagneticapparatus 115 shown in FIG. 6 is disposed both above an below theconjoined body 10, and comprises two electromagnets, each formed of arespective core 16 a, 16 b, which is of width larger than the length ofthee radius of the largest track of the slave medium 2, around whichrespective coils 17 a, 17 b have been wound. The magnetic transfermethod employing this electromagnetic apparatus 15 is substantially thesame as that described above. If the electromagnetic apparatus 15 isemployed, it becomes possible to easily change the direction andintensity of the magnetic field.

[0078] Next a detailed explanation of the master medium and the slavemedium will be provided.

[0079] As described above, the master medium 3 comprises a substrate 3 ahaving protrusion portions formed in a pattern on the surface thereof,and a pliable magnetic layer 3 b formed on said surface (over theprotrusion portions and the depression portions between the protrusionportions). A synthetic resin, a ceramic material, an alloy, aluminum,glass, quartz, silicon, nickel, or the like is used to form thesubstrate 3 a of the master medium 3. Further, as to the materialforming the pliable magnetic layer, Co, a Co alloy (CoNi, CoNiZr,CoNbTaZr, or the like), Fe, an Fe alloy (FeCo, FeCoNi, FeNiMo, FeAlSi,FeAl, FeTaN), Ni, a Ni alloy (NiFe), or the like can be employedtherefor; it is particularly preferable that FeCo, or FeCoNi beemployed. For cases in which the substrate 3 a is a ferromagnetic bodyformed of Ni or the like, although it is not necessary to provide themagnetic layer 3 b, the magnetic transfer can be improved if a magneticlayer 3 b is provided. If the substrate 3 a is formed of a non-magneticbody, it is necessary to provide the magnetic layer 3 b.

[0080] The protrusion portions of the pattern on the data bearingsurface of the master medium 3 can be formed by use of a stampingmethod, a photolithography method, or the like. Hereinafter, a simpleexplanation of the method of manufacturing the master medium will beexplained.

[0081] First, a layer of photoresist is formed on the smooth, flatsurface of a glass substrate (or a quartz substrate) by use of a spincoating process; then, a laser beam (or an electron beam), which ismodulated in correspondence to a servo signal, is emitted while thisglass substrate is being rotated, and a predetermined pattern, such asthat of a servo signal extending linearly in the radial direction fromthe rotational center of each track, is exposed over the entire surfaceof the photoresist on the portions corresponding to each frame on thecircumference. Then, the photoresist is subjected to a developmentprocess, the exposed portion of the photoresist is removed and anoriginal disk having an uneven pattern formed by the remainingphotoresist is obtained thereby. Next, the surface of the uneven patternthus formed on the surface of the original disk is subjected to aplating process (electroforming), whereby an Ni substrate having apositive uneven pattern is formed; said Ni substrate is then peeled awayfrom the original disk. This Ni substrate can be employed as a mastermedium as is, or after a pliable magnetic layer or a protective layerhas been further applied over the uneven pattern thereof, as required.

[0082] Further, the aforementioned original disk can be metal plated toform a second original disk, and this second original disk used toperform a further metal plating process, whereby a substrate having anegative uneven pattern can be formed. Also, a third original disk canbe formed by metal plating the second original disk or by hardening of asynthetic resin impressed onto the second original disk; this thirdoriginal disk can be metal plated to obtain a substrate having apositive uneven pattern.

[0083] On the other hand, after the uneven pattern has been formed ofphotoresist on the glass substrate, etching can be performed to formgrooves in the glass substrate, whereby a substrate from whichphotoresist has been removed can be obtained; a substrate can be formedtherefrom based on any of the methods described above.

[0084] Ni or a Ni alloy can be used as the material to form a metallicsubstrate, and any of various types of methods of forming a metalliclayer, including electroless deposition methods, electroformationmethods, spin coating methods, and ion plating methods can be employedas the plating method used to form this substrate. It is preferable thatthe height of the protrusions (the depth of the uneven pattern) formedon the substrate be in the range 50-800 nm; more preferably, in therange of 80-600 nm. For cases in which this uneven pattern is that of aservo signal, said pattern is formed long in the radial direction ofthereof. For example, it is preferable that the length in the radialdirection be 0.05-20 μm, and 0.05-5 μm in the circumferential direction;it is preferable that a pattern of this type, in which the length in theradial direction is long and within this range, is selected as thepattern for bearing servo signal data.

[0085] The magnetic layer 3 b, which is provided on the uneven patternof the substrate, is formed of a magnetic material and by use of avacuum layer forming means such as a vacuum deposition method, asputtering method, an ion plating method, or by a metal plating method,etc. It is preferable that the thickness of the magnetic layer 3 b be inthe range of 50-500 nm; more preferably, in the range of 80-300 nm.

[0086] Note that it is preferable that a 5-30 nm Diamond Like Carbon(DLC) film or other type of protective layer be formed over the pliablemagnetic layer of the surface of the protrusion portions, and that alubricating layer also be provided. Also, it is also possible to providea contact enhancing layer formed of Si or the like between the pliablemagnetic layer and the protective layer. The lubricant serves to improvethe durability with respect to surface damage due to friction or thelike when correcting misalignments occurring during the conjoiningprocess.

[0087] Note that according to the forgoing description, a master mediumon which an uneven pattern has been formed on the surface thereof hasbeen explained; however, a master medium having a flat surface formed byfilling in the depression portions of the uneven pattern formed thereonwith a magnetic layer can also be employed. In this case, the magneticlayer filling in the depression portions region can be a pattern formedin the same manner as a substrate having an uneven pattern.

[0088] The slave medium 2, as described above, is a disk shaped magneticrecording medium such as a hard disk, an HD flexible disk or the like;wherein the magnetic recording layer thereof is formed by coating alayer of magnetic material, or by forming a thin metallic magnetic filmrecording layer on the surface thereof. Note that here, a magnetic layeris provided with magnetic anisotropy and has an easy magnetization axisin the direction perpendicular to the track surface thereof. As to thematerial forming the thin metallic magnetic film recording layer, Co, aCo alloy (CoPtCr, CoCr, CoPtCrTa, CrNbTa, CoCeB, CoNi or the like), Fe,or an Fe alloy (FeCo, FeP, FeCoNi) can be employed therefor. Note thatit is preferable that a non-magnetic sub layer be provided so as toprovide the magnetic anisotropy required beneath the magnetic material(on the support body side thereof). A crystalline structure and alattice coefficient must be matched to the non-magnetic sub layer; tothis end, Cr, CrTi, CoCr, Crta, CrMo, NiAl, Ru, Pd or the like isemployed. Further, it is preferable that a backing layer for stabilizingthe state of the perpendicular magnetization of the magnetic layer, andimproving the recording and playback sensitivity be provided under thenon-magnetic sub layer.

[0089] Note that it is preferable that the thickness of the magneticrecording layer be greater than or equal to 10 nm and less than or equalto 500 nm, and more preferably, greater than or equal to 20 nm and lessthan or equal to 200 nm. Further, it is preferable that the thickness ofthe non-magnetic layer greater than or equal to 10 nm and less than orequal to 150 nm, and more preferably, greater than or equal to 20 nm andless than or equal to 80 nm. Still further, it is preferable that thethickness of the backing layer greater than or equal to 50 nm and lessthan or equal to 2000 nm, and more preferably, greater than or equal to80 nm and less than or equal to 400 nm.

What is claimed is:
 1. A magnetic transfer method comprising the stepsof: conjoining the magnetic layer, which has been formed in a patternfor transferring data to the magnetic layer of a slave medium, of amaster medium with the magnetic layer of the slave medium to form aconjoined body, and applying a transfer magnetic field to the respectivemagnetic layers of the conjoined master medium and slave medium tomagnetically transfer the data to the magnetic layer of the slavemedium, wherein said slave medium is a perpendicular magnetic recordingmedium, and after the magnetic layer of said slave medium has beensubjected to an initial magnetization process consisting of applying aninitial direct current magnetic field to said magnetic layerunidirectionally in a direction perpendicular to the track directionthereof to initially magnetize said magnetic layer, the magnetic layerof said slave medium and the magnetic layer of the master medium areconjoined and a transfer magnetic field is applied to the respectivemagnetic layers thereof in the direction opposite that in which theinitial direct current magnetization has been performed.
 2. A magnetictransfer method as defined in claim 1, wherein the intensity of thetransfer magnetic field is greater than or equal to 0.5 times and lessthan or equal to 3.5 times the coercive force of the magnetic layer ofthe slave medium.
 3. A magnetic transfer method as defined in claim 1,wherein the magnetic transfer master medium comprises a substrateprovided with a surface on which an uneven pattern corresponding to thedata has been formed, and a magnetic layer formed on at least thesurface of the protrusion portions of said substrate, whereby themagnetic layer of the master medium, which has been formed in a pattern,is constructed by the magnetic layer formed on said surface of theprotrusion portions.
 4. A magnetic transfer method as defined in claim1, wherein said data represent servo signals.
 5. A magnetic transfermethod as defined in claim 1, wherein said conjoined body formed of theconjoined master medium and slave medium is moved relative to thetransfer magnetic field, which is generated over a region that isnarrower than the track region, so as to pass the entirety of the trackregion of said slave medium through the transfer magnetic field.
 6. Amagnetic transfer method as defined in claim 5, wherein said slavemedium is a of discoid shape having concentric circular tracks, saidregion narrower than the track region has a width spanning a regionextending in the radial direction from the track of the smallest radiusof the slave medium to the track of the largest radius of the slavemedium, wherein the relative movement consists of rotating the conjoinedbody formed of the conjoined slave medium and master medium relative tothe transfer magnetic field along the track thereof.
 7. A magnetictransfer method as defined in claim 5, wherein said slave medium is of adiscoid shape having concentric circular tracks, said region narrowerthan the track region has a width wider than the diameter of the trackof the largest radius of the slave medium, wherein the relative movementcan consist of linearly moving the conjoined body formed of theconjoined slave medium and master medium.
 8. A magnetic transferapparatus for applying a transfer magnetic field to the conjoined bodyformed of a magnetic transfer master medium having a magnetic layerformed in a pattern for transferring data to a slave medium, and theslave medium provided with a magnetic layer, to magnetically transfersaid data to the magnetic layer of the slave medium, comprising: aninitial magnetizing means for subjecting the magnetic layer of the slavemedium to an initial magnetization process consisting of applying aninitial direct current magnetic field to said magnetic layerunidirectionally in the direction perpendicular to the track surfacethereof to initially magnetize said magnetic layer unidirectionally inthe direction perpendicular to said track surface, and a transfermagnetic field applying means for applying a transfer magnetic field tosaid conjoined body formed of the master medium and the slave medium inthe direction opposite that in which the initial magnetization has beenperformed.
 9. A magnetic transfer apparatus as defined in claim 8,wherein the intensity of the transfer magnetic field is greater than orequal to 0.5 times and less than or equal to 3.5 times the coerciveforce of the magnetic layer of the slave medium.
 10. A magnetic transferapparatus as defined in claim 8, wherein the magnetic transfer mastermedium comprises a substrate provided with a surface on which an unevenpattern corresponding to the data has been formed, and a magnetic layerformed on at least the protrusion portions surface of said substrate,whereby said pattern formed magnetic layer is formed by disposing themagnetic layer on the surface of said protrusion portions.
 11. Amagnetic transfer apparatus as defined in claim 8, wherein said datarepresent servo signals.
 12. A magnetic transfer apparatus as defined inclaim 8, wherein the transfer magnetic field applying means also servesas the initial magnetizing means.
 13. A magnetic transfer apparatus asdefined in claim 8, wherein said transfer magnetic field applying meanscomprises: a transfer magnetic field generating means for generating atransfer magnetic field on a region of the slave medium narrower thanthe track region thereof, and a moving means for moving the conjoinedbody formed of the conjoined master medium and slave medium relative tosaid transfer magnetic field so as to pass the entirety of the trackregion of said slave medium through the transfer magnetic field.
 14. Amagnetic transfer apparatus as defined in claim 13, wherein, saidmagnetic transfer field generating means is an electromagneticapparatus.
 15. A magnetic transfer apparatus as defined in claim 13,wherein said magnetic transfer field generating means is a permanentmagnet apparatus.
 16. A magnetic transfer apparatus as defined in claim13, wherein, the transfer magnetic field generating means is a means forgenerating a transfer magnetic field over the region extending in theradial direction from the track of the smallest radius of a discoidslave medium to the track of the largest radius of said slave medium,which has concentric circular tracks, and said moving means is a meansfor rotating said conjoined body relative to the transfer magnetic fieldalong said tracks.
 17. A magnetic transfer apparatus as defined in claim13, wherein, said transfer magnetic field generating means is a meansfor generating a transfer magnetic field across a region narrower thanthe track region of the slave medium and having a width larger than thediameter of the track of the largest radius thereof, and said movingmeans is a means for moving said conjoined body in a linear directionrelative to the transfer magnetic field so as to pass the entirety ofsaid track surface of the slave medium through said transfer magneticfield.